30 Carbine Case Bulge Near Head

I started reloading 30 Carbine today but had to stop due to quickly noticing a problem with my brass. All of it is bulged on one side near the case head, enough so I can feel it with my finger. This is present in both "raw" and resized/expanded brass. It still meets SAAMI specs for the dimensions of the case but it's a bit out of round.

https://www.milsurps.com/images/impo...i4d4udlx-1.jpg

It's a bit hard to see but there is daylight on the on the left hand side due to the bulge. I loaded a couple inert rounds that are just an unprimed case and a round and it chambers, goes fully into battery, and feeds fine, but I'm really concerned about this. I took the bolt out of the gun and put a live/new round in the chamber and it sits the exact same way as the reloaded, bulged round, and exactly like it should (ie the bulged spot isn't sticking out of the rear of the chamber).

What could be causing this, and is the brass safe to use? It's the same on my Aguila, PPU, and Federal brass, all shot from the same gun though it's less obvious on the Federal and PPU which do tend to come out of the gun cleaner than the Aguila, perhaps due to sealing better.

Edit: I'm asking on here as I've heard some inconsistent stuff on the net - some say it's normal and toss the brass, some say it's a headspace or chamber issue, others say the brass may be fine to reload, etc, so hoping to hear what people on here say.

Completely normal. Brass fine for re-use. Poster seems unaware that cases have to be made smaller than smallest normal chamber - otherwise we can't get them in! Guess he's never heard of "tolerances".

Extractor forces chambered case to opposite wall, resulting in "out of round" perception. Actually, where expanded, it's just as round as the chamber.

There's plenty of real stuff to fuss about when handloading. No need to invent imaginary problems.

Seems like the chamber has been mis -reamed or over polished I would think. Is this the first time you loaded for this particular gun or something that you just noticed after a recent outing or after a lot of previous use? Maybe a chamber cast could reveal more. Try to find out if the problem is with a particular portion of the chamber or random and dont measure the rim with your calipers while looking at the walls of the case, you may not have a problem at all.

Didn't think about the extractor, thanks Para shooter.

I agree that there's no problem and carry on sizing and loading. All will be fine after full length resize.

The only thing to worry about with the 30 carbine is the case length. Once you have sized it then measure it to be sure it is less the 1.290 in length. Trim to about 1.285 which seems to be where most factory ammo is. If it gets too long it can cause an out of battery discharge which is not good for anything or anyone.

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Originally Posted by Bruce McAskill

The only thing to worry about with the 30 carbine is the case length.

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Absolutely correct.

I can't argue with the case length and you can't make them to short either

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Originally Posted by TDH

You can't make them too short either

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I'm not following you on that - seems to me like too short would cause some problems. Or, do you mean only a few thousandth's under specs? - Bob

As most everyone else has said, your case looks fine. It's simply the product of a slightly large chamber, and nothing to worry about.

On the subject of reloading...It seems that most reloading manuals specify 1.280" as the trim to length. That is fully .010" shorter than the minimum headspace dimension of 1.290". That's a lot of Headspace by any account, even though it appears to not cause any functional problems in most carbines.
It is well known that brass flow in .30 Carbine cases when sizing is particularly bad, and repeated trimming due to forward brass flow will contribute to premature case life due to eventual head separation. For once fired cases, I will full length size and trim to 1.285". For subsequent loading's, I will run the cases into the full length sizer measure the case length, and adjust the die depth until that 1.285" dimension is reached then stop. My cases still have enough tension to hold the projectile firmly.

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Originally Posted by TDH

you can't make them to short

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What I think he was trying to say was don't under length trim them. I used an RCBS trim die and then they were all the same all the time. They all went through it every time, came out all the same. That sure helped, along with FL resizing. I had no problems then.

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Originally Posted by jakester

. . . For subsequent loading's, I will run the cases into the full length sizer measure the case length, and adjust the die depth until that 1.285" dimension is reached then stop. My cases still have enough tension to hold the projectile firmly.

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Unless I'm mis-reading, this appears to advocate partial sizing. If so, that's not generally a great idea for self-loading arms. Should an over-large case stall while chambering, an out-of-battery "slamfire" may occur. Complete F-L sizing can help prevent this rare but serious consequence.

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Originally Posted by Parashooter

this appears to advocate partial sizing.

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Seems to. I'd FL resize too, never had any problems that way and bullet retention was always correct.

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Originally Posted by browningautorifle

What I think he was trying to say was don't under length trim them..

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That's what I meant to say

Thanks for the advice everyone. I went and finished up my run this morning and they look great but won't get a chance to shoot it, it's been pretty windy here so my range trip today was just for defensive pistol practice. I hope to go out and verify my 8mm load in Mausers (about a month in the making) at the same time too.

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Originally Posted by Parashooter

Unless I'm mis-reading, this appears to advocate partial sizing. If so, that's not generally a great idea for self-loading arms. Should an over-large case stall while chambering, an out-of-battery "slamfire" may occur. Complete F-L sizing can help prevent this rare but serious consequence.

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Yeah, now that I think of it, not the best advice to have given a new handloader. I can get away with that procedure because my sizing die is a bit on the small side. The O.P.'s die may not be.

I've had friends bring me ammo that wouldn't hold the bullet and they blamed the brass. I have no idea what they'd done wrong, dies, sizing practice...but when I FL sized the brass in my RCBS dies, they all worked. It's just a better practice I find. As you say, dies may be different...

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Originally Posted by jakester

Yeah, now that I think of it, not the best advice to have given a new handloader. I can get away with that procedure because my sizing die is a bit on the small side. The O.P.'s die may not be.

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With your dies, is the benefit of your "procedure" that, as long as the cases are all from the same lot and fired from the same chamber, the rest of the cases won't need checked for length after sizing? I can see where that might work. I just went out to the shop and checked a bunch of "emptys" of various headstamps and fired from two different carbines. I found case lengths to be anywhere from 1.273" to 1.296" - a lot of variation, but when I picked out a few that I know were from the same lot and fired from my own carbine, they were fairly uniform in length. I can see where you might save a lot of effort on the resizing with that method too; those tapered cases can take a lot of force to FL resize. - Bob

The force is negligible with a press. You don't feel it, or you shouldn't. Cases stretch at different rates, they expand and when sized down in diameter the metal has to go somewhere so they get longer. I found the pressure involved in the firing, as a light v/s heavy load would have effect on stretch and swell... Therefore would have effect on how much they stretch, or need trimmed. They ALL need checked EVERY time.

Something I learned about loading .30 M1 that has paid off in both reliability and accuracy is to invest in a taper crimp die and use it religiously. I've been reloading for the Carbine using WW296 and 100 -110 grain projectiles with great success for more years than I care to admit.

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Originally Posted by Brian Dick

taper crimp die

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Yep, and the same for all straight wall cartridges...

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Originally Posted by USGI

With your dies, is the benefit of your "procedure" that, as long as the cases are all from the same lot and fired from the same chamber, the rest of the cases won't need checked for length after sizing? I can see where that might work. I just went out to the shop and checked a bunch of "emptys" of various headstamps and fired from two different carbines. I found case lengths to be anywhere from 1.273" to 1.296" - a lot of variation, but when I picked out a few that I know were from the same lot and fired from my own carbine, they were fairly uniform in length. I can see where you might save a lot of effort on the resizing with that method too; those tapered cases can take a lot of force to FL resize. - Bob

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Hi Bob

Actually, the reason is that my sizing die is smaller than what would be termed a small base die, it is more like a production die. If I set it so that the shell holder touches the bottom of the die, it will size my previously trimmed brass (all from the same lot) to over 1.290". So, I back off the die as necessary until it sizes the cases to 1.285". Bullet retention is solid with no setback during firing. The side benefit, was that measurement of subsequent sizing's of those same cases after firing showed that they would all size back to between 1.284"-1.287" for at least the next 3 loading's before trimming was necessary. I use the same load all the time, so I don't get many dimensional anomalies.

*Disclaimer to all*

Please understand, I don't advocate anyone follow this procedure, I only explained it because it has cut back on how often I have to trim cases. That is the main benefit. This works for me, but may not work for anyone else. If anyone disagrees with this, then just do it the way that works for YOU. The bottom line, is to know YOUR equipment.

After many delays I finally got to the range today. Everything shot and fed fine without issue, and I found a load that I'm pretty happy with. Overall pretty easy to load for, and while I just got a ton of Armscor to plink with it'll be nice to have a load for matches and in case I start to run short on supplies.

Good to hear, it's not wasted time if everything runs correctly in the end.